package com.totoro.security.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

public class MyFilterSecurityInterceptor extends AbstractSecurityInterceptor
		implements Filter {
	
	//与applicationContext-security.xml里的myFilter的属性securityMetadataSource对应，  
	//其他的两个组件，已经在AbstractSecurityInterceptor定义 
	
	@Autowired
	private FilterInvocationSecurityMetadataSource mySecurityMetadataSource;

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);

	}


	public Class<? extends Object> getSecureObjectClass() {
		return FilterInvocation.class;
	}

	public void invoke(FilterInvocation fi) throws IOException,
			ServletException {
		// object为FilterInvocation对象  
		//super.beforeInvocation(fi);源码  
		//1.获取请求资源的权限  
		//执行Collection<ConfigAttribute> attributes = SecurityMetadataSource.getAttributes(object);  
		//2.是否拥有权限  
		//this.accessDecisionManager.decide(authenticated, object, attributes);  
		InterceptorStatusToken token = super.beforeInvocation(fi);

		try {
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		} finally {
			super.afterInvocation(token, null);
		}

	}

	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return this.mySecurityMetadataSource;
	}

	public void setSecurityMetadataSource(
			FilterInvocationSecurityMetadataSource mySecurityMetadataSource) {
		this.mySecurityMetadataSource = mySecurityMetadataSource;
	}

	public void destroy() {

	}

	public void init(FilterConfig filterconfig) throws ServletException {

	}

}
